MEMS micro-mirror device

ABSTRACT

A MEMS micro-mirror device includes, a single package; a first mirror and second mirror, wherein at least one of the mirrors is configured to oscillate along an oscillation axis; wherein both mirrors are located within the single package and are arranged such that as the at least one mirror oscillates, the light incident on the first micro-mirror can be deflected to the second mirror.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.13/706,142, filed on Dec. 5, 2012 (now issued as U.S. Pat. No.9,285,668), which is a Continuation of International Patent ApplicationNo. PCT/EP2010/059386, filed Jul. 1, 2012, the subject matter of whichare incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention concerns a MEMS micro-mirror device, inparticular, but not exclusively, a MEMS micro-mirror device which issuitable for use in a projection system. The present invention alsorelates to a method for manufacturing such a device and a method ofprojecting an image onto a display screen.

DESCRIPTION OF RELATED ART

A MEMS micro-mirror device is a device that contains an optical MEMS(Micro-Electrical-Mechanical-System). The optical MEMS may comprise acylindrical, rectangular or square micro-mirror that is adapted to moveand to deflect light over time. The micro-mirror is connected bysuspended arms to a fixed part and can tilt and oscillate along one ortwo axis. For example it can oscillate vertically and horizontally.Different actuation principles can be used, including electrostatic,thermal, electro-magnetic or piezo-electric. MEMS devices are known inwhich the area of these micro-mirrors are around a few mm2. In thiscase, the dimensions of the MEMS device, comprising the packaging, isaround ten mm2. This device is usually made of silicon, and can beencapsulated in a package that can include the driving actuationelectronics. Various optical components, such as for example lenses,beam combiner, quarter-wave plates, beam splitter and laser chips, areassembled with the packaged MEMS to build a complete system.

A typical application of the MEMS micro-mirror devices is for opticalscanning and projection systems. Each of these applications requires asystem that is able to actuate the device and to detect the tiltingangle of the micro-mirror at any time. For optical scanningapplications, such as optical spectrometers and barcode scanner, thescanning operation has for example to be synchronized with themeasurement system and the detection scheme.

In a projection system, a 2-D image or a video can be displayed on anytype of surface. In a colour system, each pixel is generated bycombining modulated red, green and blue laser light sources, by meansof, for example, a beam combiner. A MEMS micro-mirror device directs thelight of the laser light source to a projection surface and reproducesthe image, or the video, pixel-by-pixel. By means of its oscillations,the micro-mirror within the device will continuously scan from left toright and from top to bottom, or according to a different trajectoryincluding e.g., Lissajou trajectories, so that each pixel of the 2-Dimage is displayed on the screen.

Typically, the micro-mirror of a MEMS micro-mirror device is able tooscillate along one axis. Therefore, in order to display a 2-D image ona screen a projection system will require two MEMS micro-mirror devices;a first MEMS micro-mirror device is required to deflect light along thehorizontal and a second MEMS micro-mirror device is required to deflectlight along the vertical. During operation, the micro-mirror of thefirst MEMS micro-mirror device receives light from the beam combiner anddeflects the light to the micro-mirror of the second MEMS micro-mirrordevice. The micro-mirror of the second MEMS micro-mirror device will inturn deflect the light to the display screen where it will appear as apixel. The micro-mirror of the first MEMS micro-mirror device willoscillate to scan the light along the horizontal thereby displaying thefirst row of pixels on the display screen. The micro-mirror of thesecond MEMS micro-mirror device will oscillate about its oscillatoryaxis so that light received from the micro-mirror of the first MEMSmicro-mirror device is scanned along the vertical. The combined effectof the oscillating micro-mirrors is that the light from the beamcombiner is scanned in a zig-zag pattern along the display screen. Theprocess is continuous so that a complete image is visible to the vieweron the display screen. The first and the second MEMS micro-mirrordevices must be precisely positioned such that the oscillatory axes oftheir respective micro-mirrors are orthogonal, otherwise all the lightreceived by the micro-mirror of the first MEMS micro-mirror device willnot be deflected to the micro-mirror of the second MEMS micro-mirrordevice as the micro mirrors oscillate. Accordingly, if precisepositioning of the two MEMS micro-mirror devices is not achieved, atleast part of the 2-D image will not be displayed on the display screen,or undesired geometric deformations will be generated. Precisepositioning of encapsulated MEMS micro-mirror devices is very difficultto achieve. Furthermore, the difficulty in attaining precise positioningof two MEMS micro-mirror devices is further compounded by the fact thatthe external dimensions and shape of the plastic or ceramic packages inwhich the MEMES devices are housed vary from batch to batch.

Other MEMS micro-mirror devices comprise a micro-mirror which canoscillate along two orthogonal axes. Such a micro-mirror can scan thelight beam in two dimensions. Therefore, to display a 2-D image on adisplay screen a projection system will require only one such MEMSmicro-mirror device.

Various methods of oscillating the micro-mirrors are employed. Forexample, a electrostatic means; thermal means; electro-magnetic means,or piezo-electric means. Accurate control of the oscillating movementsof the micro-mirrors has proven difficult in the past; for example, theaccurate control of oscillation of the micro-mirrors by electro-magneticmeans has not been possible due to varying magnetic field strengthsalong an electrical coil used to generate the magnetic field whichimparts an oscillating movement on the mirrors.

A further problem with existing MEMS micro-mirror devices is that lightfrom the laser source (e.g., beam combiner) must be transmitted to themicro-mirror within the device through a front end of the MEMSmicro-mirror device; take for example an existing MEMS micro-mirrordevices which comprises a micro-mirror which can oscillate along twoorthogonal axes; light from a laser source, such as a beam combiner,must be transmitted to the micro-mirror within the device through afront end of the MEMS micro-mirror device. The light is receiveddirectly by the micro-mirror. As the micro-mirror oscillates along itstwo orthogonal oscillation axes a 2D image is projected onto theprojection screen. Disadvantageously, since the light laser source mustbe transmitted to the micro-mirror within the device through a front endof the MEMS micro-mirror device, parasitic light coming from the lasersource will interfere with the light being projected out of the MEMSmicro-mirror device towards the display screen. The parasitic lightimpacts on the projected light to compromise the quality of the 2D imagevisible on the display screen.

It is an aim of the present invention to obviate or mitigate one or moreof the aforementioned disadvantages.

BRIEF SUMMARY OF THE INVENTION

According to the present invention there is provided, a MEMSmicro-mirror device comprising, a single package; a first mirror andsecond mirror, wherein at least one of the mirrors is configured tooscillate along an oscillation axis; wherein both mirrors are locatedwithin the single package and are arranged such that as the at least onemirror oscillates, the light incident on the first micro-mirror can bedeflected to the second mirror.

A mirror is any which is capable of reflecting light. For example, theterm ‘mirror’ includes, but is not limited to, a reflecting means,micro-mirror, a reflective element such as a metallic element, areflective surface such as a metallic surface.

Preferably, both mirrors are arranged such that as the at least onemirror oscillates, all the light incident on the first micro-mirror canbe deflected to the second mirror.

The first mirror may be configured such that it can oscillate along afirst oscillation axis, and the second mirror may be configured suchthat it can oscillate along a second oscillation axis.

The second oscillation axis may be orthogonal to the first oscillationaxis. This may ensure that all light incident on the first micro-mirrorcan be deflected to the second mirror as both micro-mirrors oscillateabout their respective axes.

As discussed above, in a projection device which uses two MEMSmicro-mirror devices each with a micro-mirror which oscillates along oneoscillation axis, the position of one MEMS micro-mirror device withrespect to the other is critical to enable projection of a 2-D image.For projection of a 2-D image the micro-mirror of one MEMS micro-mirrordevice must be precisely positioned such that its oscillation axis isexactly orthogonal to the oscillation axis of the micro-mirror of theother MEMS micro-mirror device.

Advantageously, since the MEMS micro-mirror device of the presentinvention comprises two mirrors, at least one of which can oscillateabout an oscillation axis, are pre-arranged within the same singlepackage so that as the at least one mirror oscillates, the lightincident on the first micro-mirror can be deflected to the secondmirror, the user is not required to precisely position two MEMSmicro-mirror devices to enable the projection of a 2-D image;positioning of the mirrors is made at manufacture of the MEMSmicro-mirror device and only depends on the manufacturing process.

In a further embodiment at least one of the first or second mirrors isconfigured to oscillate along two orthogonal axes. This will enable theat least one mirror to scan light in two dimensions (i.e., horizontallyand vertically). Preferably, the first mirror is fixed and the secondmirror is configured to oscillate along two orthogonal axes.

Advantageously, in this particular embodiment since the second mirrorscans light in two directions (horizontally and vertically), thisobviates the need for a second oscillating mirror to enable projectionof a 2-D image. However, to ensure projection of an uncompromised 2-Dimage all the light received by the first mirror must be deflected tothe second mirror; for this to occur the mirrors must be correctly andaccurately aligned. As with the first embodiment since the first andsecond mirrors are pre-arranged within the same single package so thatas the second mirror oscillates, the light incident on the firstmicro-mirror can be deflected to the second mirror, the user is notrequired to precisely position mirrors, or two or more MEMS micro-mirrordevices, to enable the projection of a 2-D image; positioning of thefirst and second mirrors is made at manufacture of the MEMS micro-mirrordevice and only depends on the manufacturing process.

A further advantage associated with the provision of two mirrors withina single package is that deflection of light within the MEMSmicro-mirror device can be achieved. Because light can be deflectedwithin the MEMS micro-mirror device the device is capable of receivinglight from a laser source which is positioned at the rear end of theMEMS micro-mirror device and project an image from the front end of theMEMS micro-mirror device. For example, laser sources, coupled with abeam combiner which are used to generate the individual pixels of theimage, can be located at the rear end of the MEMS micro-mirror deviceand can be arranged to transmit light through the rear of the MEMSmicro-mirror device; light transmitted through the rear of the MEMSmicro-mirror device is received by the first mirror and deflected withinMEMS micro-mirror device the towards the second mirror so that thesecond mirror projects the light through the front end of the MEMSmicro-mirror device and onto the projection screen. The provision of twomirrors within the single package allows deflection of light within thedevice; without the provision of a second mirror the beam combiner wouldneed to be positioned at the front end of the MEMS micro-mirror deviceso that the single mirror could receive the light directly from the beamcombiner and reflect the light towards the projection screen and displaythe 2D image. In this case parasitic light coming from the bean combinerand/or from an interface between the air and glass of the singlepackage, would interfere with the light projected out of the MEMSmicro-mirror device to compromise the quality of the 2D image visible onthe screen. Advantageously, in the present invention, since light can betransmitted through the rear of the MEMS micro-mirror device, theparasitic light of the air-glass interface cannot impact on the lightprojected out of the front end of the MEMS micro-mirror device; thus thepresent invention allows a clearer image to be projected on to theprojection screen.

The area within the single package may be a vacuum. The area within thesingle package may comprise a specific gas which enables increasedmechanical, optical and/or long term reliabilities performances. Forexample, the area within the single package may comprise Argon. Theprovision of Argon within the single package will facilitate reliabilityin case of a laser chip being located within the package.

The single package may comprise one or more portions which is/aretransparent to light, to allow light to enter the single package. Theone or more portions which is/are transparent to light, may also allowlight to exit the single package. For example, the single pack maycomprise one or more transparent windows. Preferably, a portion of thesingle package which is transparent to light is arranged to allow lightto exit a front end of the single package. Preferably, a portion of thesingle package which is transparent to light is arranged to allow lightto enter the single package from a rear end of single package. This willenable a mirror within the single package to receive light from anexternal laser source located at the rear of the MEMS micro-mirrordevice, thus mitigating the problems associated with parasitic lightfrom the laser source. For example, a beam combiner used to generate theindividual pixels of the image can be located to the rear and stilltransmit light to a mirror within the single package, since the beamcombiner is located at the rear of the single package light transmittedby the beam combiner will not interfere with the light projected out ofthe front end single package.

Preferably, the geometrical characteristics of the external laser sourceand optics (e.g., beam combiner) may be adapted in dimensions andgeometrical orientation with the MEMS micro-mirror device to facilitatethe assembly and the alignment of MEMS micro-mirror device and lasersource.

The single package may comprise a ceramic component. For example thesingle package may comprise a ceramic housing. Advantageously, a ceramicpackage will reduce, or prevent, parasitic light reflection which occurwithin the MEMS micro-mirror device. The single pack could be a ‘chippackage’ or a housing in which a chip can be housed to enable the chipto be electrically and mechanically connected to a printed circuitboard. For example the chip package could enable the chip to beconnected to the circuit board by means of plugging into (socket mount),or soldering onto (surface mount), the printed circuit board. The chippackage or housing may be provided with metal leads, or “pins”, whichare sturdy enough to electrically and mechanically connect the chip tothe printed circuit board.

The single package of the MEMS micro-mirror device may comprise a capmember. The single package of the MEMS micro-mirror device may furthercomprise a base member. The cap member, base member, and a wafer inwhich a mirror is formed, may define the single package in which thefirst and second mirrors are located. The cap member may be positionedsuch that the cap member, base member, and a wafer in which a mirror isformed, define the single package in which the first and second mirrorsare located. The base member may define the rear end of the MEMSmicro-mirror device and the cap member may define the front end of theMEMS micro-mirror device.

The base member may be configured such that a mirror located within thesingle packet can receive light from an external light source. This willenable a mirror within the single packet to receive light from anexternal laser source located at the rear of the MEMS micro-mirrordevice, thus mitigating the problems associated with parasitic lightfrom the laser source and the optical interfaces. For example, a beamcombiner used to generate the individual pixels of the image can belocated to the rear of the MEMS micro-mirror device so that lighttransmitted through the beam combiner will not interfere with the lightprojected out of the front end of the MEMS micro-mirror device. The basemember may comprise a transparent window. The base member comprises atransparent glass sheet.

The cap member may be configured such that a mirror within the singlepackage can project light through the cap member towards the projectionscreen. This will enable light to be projected out of the front end ofthe MEMS micro-mirror device towards a projection screen. Furthermore,it makes it possible for a mirror within the package to receive lightfrom an external light source located at the front end the MEMSmicro-mirror device. For example, the mirror will be able to receivelight from a laser source such as a beam combiner which is locatedoutside and at the front end of the MEMS micro-mirror device. The capmember may comprise a transparent window. The cap member may comprise atransparent glass sheet.

The cap member may further comprise a spacer wafer.

The spacer wafer may further comprise a tapered edge.

At least one of the first or second mirrors may be larger than theother. For example, the second mirror may be larger than the firstmirror. For example, in the case of the embodiment of the MEMS micromirror device in which the first mirror is configured such that it canoscillate along a first oscillation axis, and the second mirror isconfigured such that it can oscillate along a second oscillation axis,the second mirror may be larger than the first mirror.

The MEMS micro-mirror device may further comprise one or more reflectingmeans. A reflecting means is any means which is capable of reflectinglight, and includes, but is not limited to, mirrors, micro-mirrors, areflective element such as a metallic element, a reflective surface suchas a metallic surface. The or each reflecting means may take anysuitable form, shape, aspect or design. The one or more reflecting meansmay be provided in addition to the first and second mirrors. The or eachreflecting means may be capable of facilitating the deflection of lightwithin the single package. The or each reflecting means may be capableof deflecting light within the single package. For example, the MEMSmicro-mirror device may further comprise a third mirror which candisplace the projected image. The MEMS micro-mirror device may comprisea reflecting means arranged such that it can deflect light from thefirst mirror to the second mirror. The MEMS micro-mirror device maycomprise a reflecting means which is arranged such that it can deflectlight from a light source to a mirror. For example, the reflecting meansmay be arranged such that it can deflect light from a laser diode chipto the first mirror. It will be understood that the MEMS micro-mirrordevice may comprise any number of reflective means. It will be furtherunderstood that the or each reflective means can be arranged in anymanner within single package to deflect light within the single packagealong any desired path.

A reflecting means may be provided on the cap member. For example, atleast one reflective means located on an inner side of the cap member. Areflecting means may be integral to the cap member. For example, areflecting means may be made integral to the cap member means ofmetallization of the cap member. A reflecting means may be secured tothe tapered edge of the spacer wafer of the cap member

The MEMS micro-mirror device may further comprise one or more lasersources. Preferably, a laser source is positioned within the singlepackage. The integration of a laser source in a MEMS package could alsobe considered for all embodiments of the present invention including aMEMS device having one single 1D or 2D mirror, or any number ofmicro-mirrors. Preferably, the laser source is a laser diode chip. Thelaser source may be arranged within the single package such that alllight from the laser source is directed to a mirror or reflective meanswithin the single package.

The MEMS micro-mirror device may further comprise electronics suitablefor operating the laser source. For example, the MEMS micro-mirrordevice may comprise electronics suitable for operating a laser diodechip. Preferably, said electronics are located within the singlepackage.

The MEMS micro-mirror device may further comprise electronics suitablefor implementing oscillation of a mirror about an oscillation axis.Preferably, said electronics are located within the single package.

The or each mirror may be oscillated about its respective oscillationaxes by at least one means selected from a group comprising of; aelectrostatic means; thermal means; electro-magnetic means, orpiezo-electric means.

The MEMS micro-mirror device may further comprise one or more opticallens.

The MEMS micro-mirror device may further comprise one or more activelens.

The MEMS micro-mirror device may further comprise one or more colourfilters.

The MEMS micro-mirror device may further comprise one or more magneticelements. The or each magnetic element may be arranged to provide amagnetic field in the region of a mirror located within the singlepackage. Providing a magnetic field in the region of the mirrorsfacilitates oscillation of the mirrors about their respectiveoscillation axes by an electro-magnetic means. Preferably, the magneticelement is a permanent magnet. The or each magnetic element may bepositioned on an outer surface of the single package. Positioning the oreach magnetic element in this manner will facilitate vacuumencapsulation of the mirrors within the single package.

A magnetic element may further comprise an aperture. Advantageously, theaperture will homogenise the magnetic field along a MEMS electrical coilof an electro-magnetic means used to oscillate the MEMS mirrors abouttheir respective oscillation axis. Thus, the aperture will facilitateaccurate control of the oscillations of the mirrors about theirrespective axes.

According to the present invention there is further provided, a MEMSmicro-mirror device comprising, a single package; at least one mirrorconfigured such that it can oscillate along an oscillation axis; and atleast one laser source, wherein, both the at least one mirror and the atleast one laser source are located within the single package.

According to the present invention there is further provided aprojection device comprising MEMS micro-mirror device according to anyof the above-mentioned embodiments. The projection device may be amobile phone.

According to a further aspect of the present invention there isprovided, A method of projecting a image onto a projection screen usinga MEMS micro-mirror device comprising a front end which has at least aportion which is transparent to light, and a rear end, which is an endopposite the front end, which has at least a portion which istransparent to light, the method comprising the steps of, receivinglight from a laser through the rear end of the MEMS micro-mirror device,deflecting light within the MEMS micro-mirror device, projecting thedeflected light through the front end of the MEMS micro-mirror device toa projection screen.

According to a further aspect of the present invention there is provideda method of manufacturing a MEMS micro-mirror device comprising thesteps of, arranging a first mirror and second mirror within a singlepackage, such that at least one of the mirrors is configured tooscillate along an oscillation axis and such that as the at least onemirror oscillates along the oscillation axis, the light incident on thefirst mirror can be deflected to the second mirror.

Preferably, the first mirror and second mirror are arranged such thatall light incident on the first mirror can be deflected to the secondmirror.

The method may further comprise the steps of, arranging a first mirrorin a single package such that the first micro mirror can oscillate alonga first oscillation axis; arranging a second mirror in the same singlepackage, such that the second micro-mirror can oscillate along a secondoscillation axis.

Preferably, the first and second mirrors are arranged such that thesecond oscillation axis is orthogonal to the first oscillation axis, sothat as both micro-mirrors oscillate about their respective axes, allthe light incident on the first micro-mirror can be deflected to thesecond mirror.

The method may comprise the step of arranging least one of the first orsecond mirrors in the single package such that it can oscillate abouttwo orthogonal axis of oscillation.

Preferably, the method of manufacturing a MEMS micro-mirror device maycomprise the steps of, arranging at least one of the first or secondmirrors in a single package such that it can oscillate about twoorthogonal axis; and arranging the other mirror in the same singlepackage such that all light incident on the other mirror can bedeflected to the mirror arranged to oscillate as it oscillates about itstwo orthogonal axis.

The method of manufacturing a MEMS micro-mirror device may comprise thestep of fixing the position of other mirror within the single package.

The method of manufacturing a MEMS micro-mirror device may comprise theof providing one or more transparent windows in the single package whichenable light to enter the single package. Preferably, the methodcomprises the step of providing a transparent window in a rear end ofthe single package. Preferably, the method comprises the step ofproviding a transparent window in a front end of the single package.

The method may further comprise the step of, providing one or morereflective means which is/are capable of deflecting light within thesingle package. Preferably, the method comprises the step of, providingone or more reflective means within the single package, which is/arecapable of deflecting light within the single package. Preferably, themethod comprises the step of, providing a reflective means within thesingle package which is capable of facilitating the deflection of light,within the single package, from the first mirror to the second mirror.

The method may further comprise the step of arranging a light sourcewithin the single package. Preferably, the method comprises the step ofarranging a laser chip within the single package on a surface of asilicon wafer. Preferably, the method may comprise the step ofelectrically connecting the light source to the silicon wafer. The lightsource may be glued to the silicon wafer. Preferably, the light sourceis be glued to the silicon wafer using a thermally conductive glue. Thelight source may be a laser chip. The light source may be a LED.

The method may further comprise the step of applying one or moremagnetic elements to the single package. Preferably, the methodcomprises the step of applying one or more magnetic elements to an outersurface of the single package.

The method may further comprise the step of forming an aperture in amagnetic element.

The method may further comprise the steps of, depositing a metal on asurface of a silicon wafer and/or depositing a metal on a surface alayered silicon-insulator-silicon (SOI) substrate; etching the metal todefine a metal platform on the surface of the silicon wafer; depositinga reflective component on the platform and on at least a portion of thesurface of the wafer; etching the silicon wafer to define a first mirrorand a second mirror.

The metal deposited on the surface of a silicon wafer may be Aluminum,Copper, Gold or any alloy comprising any one of these metals. Thereflective component may comprise Aluminum, Titanium, Magnesium Silveror Gold or any alloy comprising any one of these metals.

The method may further comprise the step of arranging the silicon waferon a base member. The base member may comprise a transparent glasssheet.

The method may further comprise the steps of, depositing a reflectivecomponent onto a glass sheet; etching the reflective component to definea reflective means; securing a spacer wafer to the glass sheet to form acap member.

The metal deposited on the glass sheet may be Aluminum, Silver,Titanium, Magnesium or Gold or any alloy composed partly by these metalsor other metals having high reflectivity in the visible and IR ranges.Preferably, metal, or metal alloy, deposited on the glass sheet willhave a reflectivity greater than 80%. Most preferably, metal, or metalalloy, deposited on the glass sheet will have a reflectivity greaterthan 90%.

The method may further comprise the step of, positioning the cap memberon the silicon wafer, such that the reflective means on the cap candeflect light from the first mirror to the second mirror.

The method may comprise the step of, positioning the cap member on thesilicon wafer, such that the cap member, silicon wafer and base memberdefine the single package within which the mirrors are located.

The method may further comprise the step of, securing the cap member tothe silicon wafer. For example, the cap member may be secured to thewafer by means of anodic bonding, gluing, eutectic bonding, softsoldering, low-temperature direct bonding or glass frit bonding.

The method may further comprise the steps of, processing a silicon waferto form a spacer element which has at least one tapered edge; securingthe spacer element to a glass sheet; depositing metal on at least asurface of the tapered edge of the spacer element and on a surface ofthe glass sheet; etching the metal to define a first reflective means onthe tapered edge of the spacer element, and optionally to define asecond reflective means on the surface of the glass sheet, and to form acap member.

The metal deposited on at least a surface of the tapered edge of thespacer element and on a surface of the glass sheet, may be Aluminum,Silver or Gold or any alloy composed partly by these metals or othermetals having high reflectivity in the visible and IR ranges.Preferably, metal, or metal alloy, deposited on at least a surface ofthe tapered edge of the spacer element and on a surface of the glasssheet, will have a reflectivity greater than 80%. Most preferably,metal, or metal alloy, deposited on at least a surface of the taperededge of the spacer element and on a surface of the glass sheet, willhave a reflectivity greater than 90%.

The method may further comprise the step of, positioning the cap membersuch that light can be deflected from the first reflective means to thefirst mirror, and from the first mirror to the second reflective means,and from the second reflective means to the second mirror. The capmember may be secured to the silicon wafer. For example, the cap membermay be secured to the silicon wafer by means, of anodic bonding, gluing,eutectic or glass frit bonding.

THE BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way of exampleonly, with reference to the accompanying drawings in which,

FIG. 1 provides a cross-sectional view of a MEMS micro-mirror deviceaccording to a first embodiment of the present invention;

FIG. 2 provides a cross-sectional view of a MEMS micro-mirror deviceaccording to a second embodiment of the present invention;

FIG. 3 provides a cross-sectional view of a MEMS micro-mirror deviceaccording to a third embodiment of the present invention;

FIGS. 4a (i)-4 d illustrate the steps involved in a method ofmanufacturing a MEMS micro-mirror device; with FIG. 4a (ii) providing aplan view of the wafer of FIG. 4a (i);

FIGS. 5a-5b illustrate an alternative step in the method ofmanufacturing a MEMS micro-mirror device;

FIG. 6 illustrates a further, optional, step in the method ofmanufacturing a MEMS micro-mirror device;

FIG. 7 provides a cross-sectional view of a further embodiment of theMEMS micro-mirror device according to the present invention;

FIG. 8 provides a cross-sectional view of a further embodiment of theMEMS micro-mirror device according to the present invention;

FIG. 9a provides a cross-sectional view of a further embodiment of thepresent invention which is a variant of the MEMS micro-mirror deviceillustrated in FIG. 8;

FIG. 9b provides a plan view of the permanent magnet 131 as used in thedevice shown in FIG. 9a ; and

FIG. 10 provides a cross-sectional view of a further embodiment of theMEMS micro-mirror device according to the present invention.

DETAILED DESCRIPTION OF POSSIBLE EMBODIMENTS OF THE INVENTION

FIG. 1 provides a cross sectional view of a MEMS micro-mirror device 1according to a first embodiment of the present invention.

The device 1 comprises a first micro-mirror 3 and a second micro-mirror5 formed in a silicon wafer 18. As is evident from the Figure, thesecond micro-mirror 5 is larger than the first micro-mirror 3.

The first micro-mirror 3 can be oscillated along a first oscillationaxis 9 by means of an electrostatic, electromagnetic, piezo-electric orthermal actuation (not shown). The second micro-mirror 5 can beoscillated along a second oscillation axis 11 by means of a secondelectrostatic, electromagnetic, piezo-electric or thermal actuation (notshown). As illustrated in FIG. 1, the second oscillation axis 11 isorthogonal to the first oscillation axis 9.

The device 1 comprises a cap member 13 and a base member 15. The capmember 13 comprises a spacer wafer 17 which is attached or bonded to afirst transparent glass sheet 19. The base member 15 comprises a secondtransparent glass sheet 21. The cap member 13 is positioned such thatthe cap member 13, base member 15, and silicon wafer 18 in which firstand second micro-mirrors 3,5 are formed, define a single package 7 whichhouses the first and second micro-mirrors 3,5.

The device 1 further comprises a reflecting means in the form of areflective metal element 23. The reflective metal element 23 is securedto the first transparent glass sheet 19 of the cap member 13.

The device 1 can be used in a projection system to project a 2-D image16 onto a display screen 14. The display screen 14 maybe, for example, asurface of a wall, or any other suitable surface onto which an imagecould be projected. During operation, each pixel of the 2-D image 16 isgenerated in a beam combiner 20 by combining modulated red, green andblue laser light sources. Light 4 passes from a beam combiner 20,through the first transparent glass sheet 19 and is incident on thefirst micro-mirror 3. Light 4 incident on the first micro-mirror 3 isdeflected to the reflective metal element 23. From there the reflectivemetal element 23 deflects the light 4 to the second micro-mirror 5.Subsequently, the second micro-mirror 5 projects the light 4, out of thedevice 1, though the first transparent glass sheet 19 and onto a displayscreen 14 where the light 4 forms a pixel of the 2-D image 16. Eachpixel of the 2-D image 16 is transmitted by the beam combiner 20 andprojected to the display screen 14 in this manner.

To display the full 2D image 16 on the display screen 14, the firstmicro-mirror 3 oscillates about the first oscillation axis 9 tocontinuously scan the light 4 from the beam combiner 20 from along thehorizontal, the second micro-mirror 5 simultaneously oscillates aboutthe second oscillation axis 11 causing the light 4 to be scanned alongthe vertical. The combined effect of the oscillating micro-mirrors 3,5is to scan the light 4 in a zig-zag path across the display screen 14 toproject a complete 2-D image, pixel-by-pixel, onto the display screen14. The speed of oscillation of the micro-mirrors 3,5 is such that, tothe viewer, it will appear that the pixels of the 2D image 16 aresimultaneously projected onto the display screen 14. The oscillation ofthe micro-mirrors 3,5 is continuously repeated so that a complete 2Dimage 16 is visible to the viewer on the display screen 14. Therefore,the user will see a complete 2D image 16 on the display screen 14. Otherscanning patterns, including Lissajou curves, can also be used forscanning a 2D image onto a displace screen.

Advantageously, since the MEMS micro-mirror device 1 comprises twomicro-mirrors 3,5 in the same single package, and the axes ofoscillation of the micro-mirrors 3,5 are orthogonal to each other, thisobviates the need for precise manual alignment of two individual MEMSmicro-mirror devices to enable 2D deflection of light 4 and projectionof a 2D image; positioning is made at manufacture of the MEMS packageand only depends on the manufacturing process. Using the presentinvention all the light 4 incident on the first micro-mirror 3 isreliably reflected to the second micro-mirror 5. Accordingly, using thepresent invention, the reliability of a projection system to project acomplete 2-D image on the display screen is improved.

FIG. 2 provides a cross sectional view of a MEMS micro-mirror device 10,according to a second embodiment of the present invention. Many of thefeatures shown of the first embodiment are shown in FIG. 2 and likefeatures are awarded the same reference numerals.

The MEMS micro-mirror device 10 comprises a cap member 12. The capmember 12 comprises a spacer wafer 22 which has a tapered edge 27. Asecond reflecting means, in the form of a second reflective metalelement 25 is deposited on the tapered edge 27.

During operation, light 4 passes from a beam combiner 20, through thetransparent glass sheet 21 and is incident on the reflective metalelement 25. Light 4 is deflected by the first reflective metal element25 towards the first micro-mirror 3. Otherwise, the MEMS micro-mirrordevice 10 operates in a similar fashion to the device 1 shown in FIG. 1.

FIG. 3 provides a cross sectional view of a MEMS micro-mirror device100, according to a third embodiment of the present invention. Many ofthe features shown of the second embodiment are shown in FIG. 3 and likefeatures are awarded the same reference numerals.

In this embodiment, the MEMS micro-mirror device 100 further comprises alaser diode chip 29 which is secured to a surface 8 of the silicon wafer18 within the single package 7. The laser diode chip 29 is modulated inorder to generate each pixel of the 2D image 16 to be displayed. Thelaser diode chip 29 has typically dimensions of 300 μm*300 μm*100 μm.The light 4 generated by the laser diode chip 29 is directed to thesecond reflective metal element 25. The light 4 is subsequentlydeflected by the second reflective metal element 25 towards the firstmicro-mirror 5. Otherwise, the MEMS micro-mirror device 100 operates ina similar fashion to the device 1 shown in FIG. 1.

FIGS. 4a (i)-4 d illustrate the steps involved in a method ofmanufacturing a MEMS micro-mirror device according to the second aspectof the present invention.

As illustrated in FIG. 4a (i) the method first involves providing asilicon wafer 31 comprising a silicon oxide layer 31 a disposed betweenan first and second silicon layer 31 b,31 c (also known as SOI-SiliconOn Insulator wafer). An Aluminum, Copper or gold layer 33 or any alloycomprising one of these metals is deposited on a surface 35 of thesilicon wafer 31. The Aluminum, Copper or gold layer 33 or any alloycomprising one of these metals is subsequently etched to define a firstmetal coil 37 and a second, group, of metal coils 38, on the surface 35of the silicon wafer 31. A reflective metal 39 is then deposited insidean area defined by the first metal coil 37 and reflective metal 39 isalso deposited inside an area defined by the smallest of the metal coilscomprised in the second, group, of metal coils 38. The reflective metalcould be Silver, Gold, Titanium, Magnesium or Aluminum or any alloycomprising one of these metals.

FIG. 4a (ii) provide a plan view of the silicon wafer 31 shown in FIG.4a (i). Most of the features illustrated in FIG. 4a (i) are also shownin FIG. 4a (ii) and like features are awarded the same referencenumerals.

As illustrated in FIG. 4b the second silicon layer 31 c and the siliconoxide layer 31 a of the silicon wafer 31, are etched. Subsequently, thesilicon layer 31 b is etched, to define a first micro-mirror 41. Theregion 46 is further etched to define a second micro-mirror 43. Thesilicon wafer 31 is then secured to a base member in the form of atransparent or semi-transparent glass sheet 45 which provides atransparent window.

FIG. 4c illustrates the steps involved in the formation of a cap member57. To form the cap member 57 a reflective component, in the form of alayer of metal 47, such as Aluminum, Ag, Titanium, Magnesium or Au metalor any alloy comprising at least one of these elements, is depositedonto a surface 51 of a transparent glass sheet 49. The layer of metal oralloy 47 is etched to define a reflector element 53 on the surface 51 ofa transparent glass sheet 49. A spacer wafer 55 is subsequently securedto the surface 51 of the transparent glass sheet 49 to form the capmember 57.

As shown in FIG. 4d , the cap member 57 is mounted on the SOI wafer 31,such that the cap member 57, SOI wafer 31 and transparent glass sheet 45(base member) define a single package 59 within which the first andsecond micro mirrors 41,43 are located. The cap member 57 is mountedsuch that light incident on the first micro-mirror 41 can be deflectedby the reflector element 53 towards the second micro-mirror 43. Thefirst micro-mirror 41 is arranged within the single package 59 such thatit can oscillate along a first oscillation axis 61 and the secondmicro-mirror 43 is arranged within the single package 59 such that itcan oscillate along a second oscillation axis 62, wherein the secondoscillation axis 62 is orthogonal to the first oscillation axis 61.

FIGS. 5a and 5b illustrate alternative steps in the method ofmanufacturing a MEMS micro-mirror device. Specifically, FIGS. 5a and 5billustrate the steps involved in forming an alternative cap member 81.To form the alternative cap member 81 a silicon wafer 32 is etched(e.g., dry etch followed by a wet etch) to form a spacer element 63 witha tapered edge 65. The spacer element 63 is secured to a transparentglass sheet 67.

As illustrated in FIG. 5b , a layer of Aluminum, Gold, Magnesium,Titanium or Silver metal 75 or an alloy composed of at least one ofthese materials, is deposited over an inner surface 71 of the spacerelement 63 and over an inner surface 73 of the transparent glass sheet67. The layer of Aluminum, Gold, Magnesium, Titanium or Silver metal 75is then etched to define a first reflector element 77 on the taperededge 65 of the spacer element 63 and a second reflector element 79 onthe inner surface 73 of the transparent glass sheet 67. Once etched thealternative cap member 81 is formed.

The alternative cap member 81 may be mounted on the silicon wafer 31,such that the cap member 81, silicon wafer 31 and transparent glasssheet 45 (base member) define a single package 80 within which the firstand second micro mirrors 41, 43 are located (The region 46 may be etchedto define the second micro-mirror 43). The alternative cap member 81 ismounted such that light can be deflected from the first reflectorelement 77 to the first micro-mirror 41, and from the first micro-mirror41 to the second reflector element 79, and from the second reflectorelement 79 to the second micro-mirror 43.

As illustrated in FIG. 6, the method of manufacturing a MEMSmicro-mirror device may further comprise the step of securing a laserchip 83 to the surface 35 of the silicon wafer 31. In the exampleillustrated in FIG. 6, the laser chip 83 is electrically connected tothe silicon wafer 31 and is attached with glue for example to secure thelaser chip 83 in position. As is evident from FIG. 6 the laser chip 83is secured within the single package 80 such that light generated in thelaser chip 83 can be incident on the first reflector element 77 andsubsequently follow the same path as described above for FIG. 5b .Optionally, an additional lens can be added to the laser chip to shapethe output light beam.

FIG. 7 illustrates a MEMS micro-mirror device 103 according to a furtherembodiment of the present invention. The MEMS micro-mirror device 103comprises a single ceramic package 70. The region inside the singleceramic package 70 is a vacuum area 115. Alternatively, the regioninside the single ceramic package 70 may not be a vacuum and maycomprise instead a specific gas such as Argon. Alternately, the regioninside the single ceramic package 70 may be a vacuum and may comprise aspecific gas, such as Argon. The provision of Argon within the ceramicpackage will facilitate reliability in case of the laser chip isembedded in the package 70. The single ceramic package 70 comprises atransparent window 105; in this particular embodiment the transparentwindow 105 is integral to the ceramic package, however it will beunderstood that the transparent window could be a separate entity andapplied over an aperture in the ceramic package 70.

The device 103 comprises a first micro-mirror 3 and a secondmicro-mirror 5 both of which are located within the single ceramicpackage 70 and thus within the vacuum area 115. As is evident from theFigure, the second micro-mirror 5 is larger than the first micro-mirror3. The first micro-mirror 3 can oscillate along a first oscillation axis9, and the second micro-mirror 5 can oscillate along a secondoscillation axis 11. The first oscillation axis 9 is orthogonal to thesecond oscillation axis 11. The first and second micro-mirrors 3,5 aresupported on (for example attached to) an inner surface 107 of thesingle ceramic package 70 and arranged such that as both micro-mirrorsoscillate about their respective axes, all light 4 which is incident onthe first micro-mirror 3 can be deflected to the second mirror 5. Thefirst micro-mirror 3 is further arranged such that it can receive light4 passing through the transparent window 105.

A first and second permanent magnet 111, 113 are located on an outersurface 109 of the single ceramic package 70. The first permanent magnet111 is positioned in the region of the first micro-mirror 3 and thesecond permanent magnet 113 is positioned in the region of the secondmicro-mirror 5. The permanent magnets are used to actuate oscillation ofthe first and second micro-mirrors 3,5. The permanent magnets 111, 113create permanent magnetic fields. When a current is applied to coilswhich cooperate with each mirror, due to the presence of these permanentmagnetic fields, a force will be generated along each coil. Since eachcoil cooperates with a respective mirror, the force generated along eachcoil will induce movement of the mirror.

The device 103 operates in a similar fashion to the device illustratedin FIG. 3. To display the full 2D image 16 on the display screen 14, amodulated laser source, which is preferably connected to a beamcombiner, will generate each pixel of the 2-D image to be projected. Thefirst micro-mirror 3 receives light 4 which defines the pixels from abeam combiner. The first micro-mirror 3 is oscillated about the firstoscillation axis 9, by an electromagnetic actuation means (not shown)and with the aid of the first permanent magnet 111, to scan the light 4along the horizontal. The second micro-mirror 5 is simultaneouslyoscillated about the second oscillation axis 11 by an electromagneticactuation means (not shown) and with the aid of the second permanentmagnet 113, causing the light 4 to be scanned along the vertical. Theoscillation of each micro-mirror 3,5 is continuous. The combined effectof the oscillating micro-mirrors 3,5 is to scan the light 4 in a raster,or zig-zag, scanning path across the display screen 14 to project acomplete 2-D image, pixel-by-pixel, onto the display screen 14. Thespeed of oscillation of the micro-mirrors 3,5 is such that, to theviewer, it will appear that the pixels of the 2D image 16 aresimultaneously projected onto the display screen 14. The oscillations ofthe micro-mirrors 3,5 is continuously repeated so that a complete 2Dimage 16 is visible to the viewer on the display screen 14.

Advantageously, positioning the permanent magnets 111, 113 on an outersurface 109 of the ceramic package 70 enables a reduction in cost ofmanufacturing the device. Usually, the ceramic package is made bysuccessive layer deposition, each layer being around 100 μm inthickness. As the magnets are large and thick, to locate the magnetswithin the package would require a large size package; the cost ofmanufacturing a large ceramic package is higher compared to the cost ofmanufacturing a small sized ceramic package. Smaller magnets could beused to allow for a reduction in the size of the package; however, theactuation of oscillation of the mirrors by smaller magnets is notreliable as the magnetic force generated by a smaller magnet is not arelarge as the magnetic force generated by a larger magnet. Furthermore,the smaller magnetic force generated by smaller magnets means that thesize, or mass, of the mirrors which can be used in the device, islimited. Advantageously, locating the magnets 111,113 outside of thepackage allows large magnets to be used without requiring a largerpackage. Furthermore, the use of a single package formed of ceramicensures that there is little, or no, parasitic light reflection withinthe MEMS micro-mirror device 103 during use. Accordingly, a clearerimage can be projected by the device onto a display screen.

FIG. 8 illustrates a MEMS micro-mirror device 120 according to a furtherembodiment of the present invention. The device 120 has many of the samefeatures as the device 103 shown in FIG. 7 and similar features areawarded the same reference numerals.

The MEMS micro-mirror device 120 comprises a first mirror, in the formof a reflective metallic element 121, which is fixed in position withinthe single package 70, and a micro-mirror 123 which is capable ofoscillating along two orthogonal oscillation axes (not shown). It willbe understood that the first mirror could take any suitable form and isnot restricted to being a metallic element 121, for example the firstmirror could be a micro-mirror. Both the metallic element 121 and themicro-mirror 123 are located within the single ceramic package 70 andthus within the vacuum area 115. The metallic element 121 and themicro-mirror 123 are each co-operate with an inner surface 107 of thesingle ceramic package 70; in the particular embodiment shown in FIG. 8the metallic element 121 is fixed directly to the inner surface 107 ofthe single ceramic package 70, and the micro-mirror 123 is supported onthe inner surface 107 such that it can oscillate about its twoorthogonal oscillation axes. The metallic element 121 and themicro-mirror 123 are arranged such that as the micro-mirror oscillatesabout its oscillation axes, light 4 incident on the metallic element 121can be deflected to the micro-mirror 123. The metallic element 121 isfurther arranged such that it can receive light 4 passing through thetransparent window 105 of the single ceramic package 70.

A permanent magnet 124 is located on an outer surface 109 of the singleceramic package 70. The permanent magnet 124 is positioned in the regionof the micro-mirror 123. The permanent magnet 124 facilitates theactuation of the oscillations of the micro-mirror 123 along its twoorthogonal oscillation axis. The permanent magnet 124 creates permanentmagnetic field. When a current is applied to coils which cooperate withthe micro-mirror 123, due to the presence of the permanent magneticfield, a force will be generated along the coil. Since the coilcooperates with the micro-mirror 123, the force generated along eachcoil will induce movement of the micro-mirror 123.

To display the full 2D image 16 on the display screen 14, a laser sourcesuch as a beam combiner will generate each pixel of the 2-D image to beprojected. The metallic element 121 receives light 4 which defines thepixels, from a beam combiner, through the transparent window 105. Themetallic element 121 deflects all the light it receives towards themicro-mirror 123. The micro-mirror 123 is oscillated by anelectromagnetic actuation means (not shown) and with the aid of thepermanent magnet 124, about its two oscillation axes, to continuouslyscan the light 4 in a raster (or zig-zag) scanning pattern across thedisplay screen 14 and thus project a complete 2-D image 16,pixel-by-pixel, onto the display screen 14.

Advantageously, since the micro-mirror 123 is capable of oscillatingalong two orthogonal axes, this obviates the need to provide a secondmirror which can oscillate in order to project a 2-D image. Furthermore,positioning the permanent magnet 124 on an outer surface 109 of theceramic package 70 enables a reduction in the cost of manufacturing thedevice. Furthermore, the use of single package 70 formed of ceramicensures that there is little, or no, parasitic light reflection withinthe MEMS micro-mirror device 120 during use. Accordingly, a clearerimage can be projected by the device onto a display screen.

FIG. 9a illustrates a further embodiment which is a variant of the MEMSmicro-mirror device 120 shown in FIG. 8. The MEMS micro-mirror device130 illustrated in FIG. 9a has many of the same features shown in theembodiment of FIG. 8 and like features are awarded the same referencenumerals.

The MEMS micro-mirror device 130 illustrated in FIG. 9a comprises apermanent magnet 131 which is arranged to extend across a transparentbase member 133 of the single package 139. The permanent magnet 131 maybe directly attached to the base member 133. As with the embodimentillustrated in FIG. 8, the permanent magnet 131 facilitates the controlof the oscillation of the micro-mirror 123 along its two oscillationaxes.

An aperture 135 is provided in the permanent magnet 131. The aperture135 is configured such that light 4 from an external laser source, suchas a beam combiner 137, can pass through the aperture 135 andtransparent base member 133 and be received by the metallic element 121.The beam combiner 137 comprises a red laser 151, a blue laser 153 and agreen laser 155. The components of the beam combiner 137, for examplecomponent 138, are shaped and have surfaces which facilitate theco-operation between the beam combiner 137 and the single package 139.

The MEMS micro-mirror device 130 illustrated in FIG. 9a operates in asimilar fashion to the device 120 shown in FIG. 8. However,advantageously, the aperture 135 in the permanent magnet 131 willhomogenise the magnetic field along a MEMS electrical coil (not shown)of an electro-magnetic means (not shown) used to oscillate the MEMSmirror 123 about its two oscillation axes. Thus, the aperture 135 willfacilitate accurate control of the oscillations of the micro-mirror 123about its two oscillation axes.

FIG. 9b provides a plan view of the permanent magnet 131 as used in thedevice shown in FIG. 9a . It is shown that the permanent magnet 131comprises three prices 131 a,131 b,131 c, which cooperate to form asingle, substantially square, permanent magnet 131. It will beunderstood that the permanent magnet 131 could comprise any number ofpieces, for example the permanent magnet 131 could be a single piece.The permanent magnet creates a permanent magnetic field 150. Thedirection of the permanent magnetic field 150 created by permanentmagnet 131 is shown. The permanent magnetic field is in the directionout of the page in piece 131 c and is in the direction into the page inpiece 131 a. The position (see dashed line) of the micro-mirror 123 withrespect to the permanent magnet 131 is also illustrated. When a currentis applied to coils which cooperate with the micro-mirror 123, due tothe presence of the permanent magnetic field 150, a force will begenerated along the coil thereby causing movement of the micro-mirror123. The aperture 135 in the permanent magnet 131 is furtherillustrated.

FIG. 10 illustrates a further a MEMS micro-mirror device 101. The device101 has many of the same features of the device shown in FIG. 3 andsimilar features are awarded the same reference numerals. The device 101comprises a single package 7. A first mirror, in the form of areflective element 250, is provided inside the single package 7 and on atapered edge 27 of the single package. A second mirror in the form of amicro-mirror 30 which is configured such that it can oscillate along atwo orthogonal oscillation axes, is located within the single package 7.A laser source, in the form of a laser diode chip 29 is secured to asurface 8 of a silicon wafer 18 within the single package 7. Thus, boththe micro-mirror 30 and the laser source are located within the singlepackage 7.

In use light 4 is generated in the laser diode chip 29 within the singlepackage 7 and is directed to the reflective element 250. The light 4generated by the laser diode chip 29 may comprise the pixels of a 2-Dimage to be displayed. The reflective element 250 deflects the light 4towards the micro-mirror 30. The micro-mirror 30 oscillates along twoorthogonal oscillation axes to scan the light in a raster scanningpattern along the display screen 14 thereby projecting a 2-D image 16onto the display screen 14 pixel by pixel.

Various modifications and variations to the described embodiments of theinvention will be apparent to those skilled in the art without departingfrom the scope of the invention as defined in the appended claims.Although the invention has been described in connection with specificpreferred embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiment.

The invention claimed is:
 1. A MEMS micro-mirror device comprising: apackage comprising: a cap member comprising a transparent portion totransmit light; and a base member, the cap member overlying the basemember; a red laser light source disposed within the package, the redlaser light source to emit a red laser light; a green laser light sourcedisposed within the package, the green laser light source to emit agreen laser light; a blue laser light source disposed within thepackage, the blue laser light source to emit a blue laser light; a beamcombiner disposed within the package, the beam combiner arranged tocombine the red laser light, the green laser light, and the blue laserlight into a visible light beam projected through the base member; and asingle mirror disposed within the package and configured to oscillateabout an oscillation axis and about a second oscillation axis, thesecond oscillation axis orthogonal to the oscillation axis, the singlemirror arranged to receive the visible light beam and reflect thevisible light beam through the transparent portion.
 2. The MEMSmicro-mirror device according to claim 1, further comprising one or moremagnetic elements.
 3. The MEMS micro-mirror device according to claim 2,wherein the or each magnetic element has an aperture.
 4. The MEMSmicro-mirror device according to claim 1, wherein the package comprisesa ceramic component.
 5. The MEMS micro-mirror device according to claim1, comprising a reflector arranged to receive the visible light beamprojected through the base member and reflect the visible light beam tothe single mirror.
 6. The MEMS micro-mirror device according to claim 1,the red laser light source, the green laser light source, and the bluelaser light source each configured to generate laser light based onpixels of a two-dimensional image to be displayed.
 7. A systemcomprising: a package, formed at least in part from a silicon substrate,the package comprising: a cap member comprising a transparent portion totransmit light; and a base member, the cap member overlying the basemember; a red laser light source disposed within the package, the redlaser light source to emit a red laser light; a green laser light sourcedisposed within the package, the green laser light source to emit agreen laser light; a blue laser light source disposed within thepackage, the blue laser light source to emit a blue laser light; a beamcombiner disposed within the package, the beam combiner arranged tocombine the red laser light, the green laser light, and the blue laserlight into a visible light beam projected through the base member; and asingle mirror, formed at least in part from the silicon substrate,disposed within the package and configured to oscillate about anoscillation axis and about a second oscillation axis, the secondoscillation axis orthogonal to the oscillation axis, the single mirrorarranged to receive the visible light beam and reflect the visible lightbeam through the transparent portion.
 8. The system of claim 7, furthercomprising one or more magnetic elements.
 9. The system of claim 8,wherein the or each magnetic element has an aperture.
 10. The system ofclaim 7, wherein the package comprises a ceramic component.
 11. Thesystem of claim 7, comprising a reflector arranged to receive thevisible light beam projected through the base member and reflect thevisible light beam to the single mirror.
 12. The system of claim 7, thered laser light source, the green laser light source, and the blue laserlight source each configured to generate laser light based on pixels ofa two-dimensional image to be displayed.